According to the DOD there are 81,864 POW/MIA's who need to be Remembered. Who have families waiting for closure of some sort. There are several ways to show our Countries Son's are NOT FORGOTTEN. You can fly a POW/MIA flag, wear a shirt like the one below found at Ranger UP.
If none of the above options work for you, at the very least you can wrap a black cloth around your upper arm in Remembrance. When someone asks why you're wearing a black arm band, tell them it is in Honor and Hope for those who have not made it home. NEVER FORGET.